1. Technical Field
The invention described in this application relates generally to tubing, and more particularly to a multilayer tube featuring beneficial extrusion and flow properties and a pleasing appearance.
2. Background Information
Tubing carrying a flow of fluid under pressure, such as irrigation tubing and the like, should exhibit properties of flexibility, strength, and durability. It should be lightweight and present minimal resistance to fluid flow, and it should employ inexpensive materials and fabrication techniques. In addition to these attributes, many users prefer tubing with a pleasing appearance.
A relatively narrow molecular weight distribution polymeric composition, such as a narrow molecular weight distribution ethylene copolymer, exhibits many of the desired attributes. However, such a composition is difficult to extrude, and this is important because extrusion is the preferred fabrication technique, enabling relatively convenient and inexpensive fabrication of the miles of tubing in demand. A narrow molecular weight distribution polymeric composition tends to stick to the extrusion die and become pitted. This results in increased resistance to fluid flowing within the finished tubing, as well as an unpleasant appearance. Thus, it is desirable to have a new and improved tubing structure that overcomes these concerns.